The cleavage of HuR interferes with its transportin-2-mediated nuclear import and promotes muscle fiber formation.

Although the function of posttranscriptional processes in regulating the expression of genes involved in muscle fiber formation (myogenesis) is well accepted, the mechanisms by which these effects are mediated remain elusive. Here, we uncover such a mechanism and show that during myogenesis, a fraction of the posttranscriptional regulator human antigen R (HuR) is cleaved in a caspase-dependent manner in both cell culture and animal models. Disruption of caspase activity in cultured myoblasts or knocking out the caspase-3 gene in mice significantly reduced HuR cleavage and the cytoplasmic accumulation of HuR in muscle fibers. The non-cleavable isoform of HuR, HuRD226A, failed to reestablish the myogenic potential of HuR-depleted myoblasts. HuR cleavage generates two fragments: HuR-cleavage product 1 (HuR-CP1) (24 kDa) and HuR-CP2 (8 kDa). Here, we show that one of these fragments (HuR-CP1) binds to the HuR import factor transportin-2 (TRN2) allowing HuR to accumulate in the cytoplasm. As this cytoplasmic accumulation is required for the promyogenic function of HuR, our data support a model, whereby during the transition phase from myoblasts to myotubes, a proportion of HuR is cleaved to generate HuR-CP1. By interfering with the TRN2-mediated import of HuR, this CP helps non-cleaved HuR accumulate in the cytoplasm thus promoting myogenesis.

Protective effects of preconditioning in cultured rat endothelial cells: effects on neutrophil adhesion and expression of ICAM-1 after anoxia and reoxygenation.

BACKGROUND: Preconditioning with brief periods of ischemia protects the coronary endothelium against acute and chronic reperfusion injury, but the mechanisms of this endothelial protection remain unknown. We hypothesized that preconditioning protects endothelial cells through a decreased production of endothelial adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1), leading to a lesser adhesion of neutrophils to the endothelium. METHODS AND RESULTS: Cultured rat aortic endothelial cells were subjected to 6-hour anoxia followed by various durations of reoxygenation. Preconditioning was induced by 1-hour anoxia and 1-hour reoxygenation. ICAM-1 gene expression was measured by polymerase chain reaction, and the percentage of cells expressing ICAM-1 was assessed by confocal laser fluorescence microscopy. Anoxia/reoxygenation increased expression of ICAM-1, with a peak occurring after 6 hours of reoxygenation for mRNA and 9 hours for protein. Preconditioning prevented the increase in ICAM-1. Similar reductions were observed with the free radical scavenger N-2 mercaptopropionyl glycine (MPG). The inhibitory effect of preconditioning on ICAM-1 expression was abolished by an inhibitor of protein kinase C, an inhibitor of nitric oxide synthesis, and by MPG but was not affected by an adenosine receptor antagonist. Finally, both preconditioning and MPG partially prevented the increased adhesion of human neutrophils to reoxygenated endothelial cells. CONCLUSIONS: Preconditioning prevented reoxygenation-induced, free radical-mediated expression of ICAM-1 by a mechanism involving activation of protein kinase C and production of nitric oxide and free radicals, and this is associated with a lesser adhesion of neutrophils to endothelial cells. Such prevention of neutrophil adhesion may contribute to the protective effect of preconditioning against reperfusion-induced endothelial injury.

Virilizing serous cystadenoma.

A 71-year-old woman, 26 years post-menopause, presented with virilization. Facial hirsuties, non-hereditary frontal balding, voice changes, male escutcheon, and mild clitorimegaly accompanied a right adnexal mass. Blood hormone studies showed testosterone 430 ng/dL, FSH 118 mIU/mL, and LH 210 mIU/mL. By ultrasound examination, the cystic adnexal mass involved the right ovary. An 18-cm, 1300-g, unicameral mass with 1200 mL of clear serous fluid and with smooth inner and outer surfaces was removed from the right broad ligament. Intraoperative testosterone levels were as follows: peripheral vein 285 ng/dL, left ovarian vein 301 ng/dL, and right ovarian vein 1635 ng/dL; tumor cystic fluid was 3032 ng/dL. Peripheral vein testosterone was 15 ng/dL 3 days postoperatively. Histopathologically, the tumor was a serous cystadenoma. No evidence of stromal luteinization, hyperplasia, or inflammation was found, and other virilizing lesions were not encountered in either ovary or in other tissues. Epithelial cells constituting the tumor may have been the source of the excess testosterone in this unique case of virilizing serous cystadenoma.

Histologic response to microsuture materials.

Long- and short-term reactions of reproductive tract tissue to microsurgical suture materials were compared. The five materials were: polyglactin 910 (Vicryl), polyglycolic acid (Dexon-S), polypropylene (Prolene), nylon (Ethilon and Dermalon) and chromic catgut; the calibers ranged from 6-0 to 10-0. Sixteen days after suture placement the smallest tissue reaction was seen with 9-0 and 10-0 suture materials; Dexon-S caused a slightly greater reaction than did Vicryl. Prolene, 8-0 and 9-0, produced the smallest tissue response when compared to other sutures of similar size. Larger sutures incited greater tissue reactions. Forty-two days after placement, each suture was associated with similar or lower reaction scores than those observed at 16 days. At 90 days all the Dexon-S sutures had been absorbed. Vicryl had less of a late reaction as compared to the other sutures. Reactions persisted longer with nonabsorbable suture, and the tissue response depended on both the suture material and caliber. Vicryl, 8-0 to 10-0, incited the smallest short- and long-term tissue reaction; at those sizes it seems optimal for reconstructive tubal surgery.

Preliminary experience with a combination of clomiphene and variable dosages of menopausal gonadotropins for enhanced follicular recruitment.

A combination of clomiphene citrate and human menopausal gonadotropin was employed for enhanced follicular recruitment in an in vitro fertilization program. All patients received 50 mg of clomiphene and 1 ampule of human menopausal gonadotropin daily from cycle day 5 through cycle day 9. Follicular monitoring was begun on day 10 using a combination of ultrasound measurement of follicular size and number and determination of peripheral estradiol levels. Based on the size and number of follicles, the peripheral levels of estradiol, and the rate of follicular growth and increase in estradiol, human menopausal gonadotropin was continued at a dosage of 1 to 3 ampules/day through the day of human chorionic gonadotropin administration. Human chorionic gonadotropin was administered on the evening of the day the largest follicle reached or exceeded 20 mm in mean diameter if the estradiol levels had been rapidly rising or reaching a plateau and had exceeded a minimal level of 300 pg/ml. Using this protocol, 30 of 33 patients underwent laparoscopy, 29 patients had successful oocyte recovery, and 23 patients underwent embryo replacement, with the establishment of six clinical pregnancies.

Evaluation of progestogens for postoperative adhesion prevention.

Progesterone (P) has been shown to have potent antiinflammatory and immunosuppressive properties. Previous reports have suggested that the use of P decreases postoperative adhesion formation. To further evaluate the role of pharmacologic doses of progestogens in adhesion prevention, 42 mature New Zealand White rabbits underwent standardized injuries to the uterine horns, fimbriae, and pelvic peritoneum and received one of six treatments. Group S had intraperitoneal placement of normal saline (0.9%); group H received intraperitoneal placement of 32% dextran 70; group IM-P received intramuscular P-in-oil 10 days before and after laparotomy in addition to intraperitoneal saline; group IP-P had intraperitoneal placement of an aqueous P suspension; group DP received medroxyprogesterone acetate intraperitoneally; and group C received no intramuscular or intraperitoneal adhesion-prevention agents. The animals were sacrificed 6 weeks after laparotomy, and the adhesions were scored. Intraperitoneal saline (group S) significantly reduced the amount of adhesions when compared with the control group (C) (P less than 0.05). No significant difference was observed when group S was compared with group H. Intramuscular P added to saline (group IM-P) did not cause further reduction in adhesions when compared with group S. Both group IP-P and group DP had more adhesions than did group S (P less than 0.01). These data fail to support previous claims regarding adhesion prevention by the use of locally or parenterally administered progestogens.

Enhanced follicular recruitment in an in vitro fertilization program: clomiphene alone versus a clomiphene/human menopausal gonadotropin combination.

In an attempt to improve the pregnancy rate following in vitro fertilization and embryo transfer by increasing the numbers of embryos available for transfer to each patient, a prospective, randomized comparison of clomiphene citrate alone (50 mg/day, cycle days 5 to 9) with the combination of clomiphene as above plus human menopausal gonadotropin (2 ampules/day, cycle days 6, 8, and 10) was undertaken from January through April 1983, with 17 patients in each group. The combination produced increased follicular development, compared with clomiphene alone, resulting in the retrieval of more fertilizable oocytes. Two clinical pregnancies resulted in each group. These results show that a fixed combination of clomiphene and human menopausal gonadotropin produces a greater degree of enhanced follicular recruitment, resulting in the recovery of an increased number of fertilizable oocytes. The lack of a statistically significant increase in the number of embryos transferred per patient in the combination group as well as the identical number of clinical pregnancies in both groups suggests that this particular combination of clomiphene and human menopausal gonadotropin offers no advantage over the use of clomiphene alone for enhanced follicular recruitment.

Estrogen replacement therapy. Universal remedy for the postmenopausal woman?

The menopausal woman is in a state of estrogen deficiency that induces a variety of metabolic, structural, and symptomatic disturbances. Indications for estrogen replacement therapy include vasomotor symptoms, psychosomatic complaints, urogenital atrophy, prevention of osteoporosis, and prevention of coronary heart disease. Potential risks of therapy include development of endometrial and breast cancer. The incidence of both can be decreased with combination estrogen-progestin therapy. Future research efforts should be directed toward identifying the postmenopausal woman at increased risk for osteoporosis and/or coronary heart disease.

Human sperm velocity and postinsemination cervical mucus test in the evaluation of the infertile couple.

Homologous artificial insemination (AIH) followed by postinsemination cervical mucus test (PIT) was performed in 100 couples in a prospective study to evaluate suspected cervical or male factor infertility. A portion of the ejaculate was submitted for standard semen analysis as well as turbidimetric analysis of sperm velocity. In a review of 333 cases evaluated for infertility, the average sperm velocity in a normal semen analysis was 96.5 mu/sec, for those with normal postcoital test (PCT) 96.6 mu/sec, and in those that established a pregnancy 91.6 mu/sec. These are significantly higher than the values obtained for abnormal semen analysis and abnormal PCT (64.6 and 63.6 mu/sec, respectively; p less than 0.001). Patients with normal PIT (WHO criteria for normal PCT consisting of greater than or equal to 7 motile sperm/hpf) had sperm velocity of 87 mu/sec compared to velocities of 46 mu/sec for abnormal PIT (p less than 0.001). Four of the five patients with abnormal PIT (in spite of normal semen analysis and normal cervical mucus) had sperm velocities less than 75 mu/sec. Likewise, all 8 patients who had normal PIT in spite of abnormal semen analysis had sperm velocities greater than 75 mu/sec, even though the sperm motility was below normal in 5 of them. Sperm velocity is a more sensitive indicator of sperm function when compared to standard semen analysis results.

Single-dose ampicillin for cesarean section prophylaxis.

A single 2-g dose of ampicillin or a placebo identical in appearance was administered intravenously in a randomized, prospective, double-blind manner to 71 patients undergoing cesarean section. The solutions were given either on call to the operating room or during the intraoperative period. Postoperative morbidity from infection occurred in 59.4% of patients receiving placebo and in 14.7% of those receiving ampicillin (P less than .0001). In those individuals undergoing primary cesarean section the incidence of infection with placebo was 65% and with ampicillin 6.3% (P less than .0004). In patients undergoing repeat cesarean section the incidence was 53% in the placebo group and 22% in the treatment group (P greater than .05). There were no differences in the effectiveness of the drug whether given preoperatively or intraoperatively. Serious infections and wound infections were not encountered in patients receiving ampicillin.

Ambulatory cardiac catheterization cuts costs for hospital and patients.

Performing cardiac catheterization on ambulatory patients has proved to be a cost-effective alternative to inpatient care that results in minimal difficulty and risk to the patient.

[A study of the tensile strength of cruciate ligaments with regard to the possibilities of prosthetic replacement (author's transl)]. / Etude des propriétés mécaniques des ligaments croisés en vue de leur remplacement prothétique.

Recent clinical and experimental results in the prosthetic replacement of the anterior cruciate ligament are minimal and this fact has incited us to search for additional fundamental characteristics of natural and synthetic ligaments. The dissection of over 30 human knees (5 fresh and 27 embalmed specimens), of 50 dog knees and of 20 cat knees showed that the posterior cruciate ligament was longer and of bigger size than the anterior cruciate ligament. In dogs, the anatomo-radiological study showed a lenghtening of 14,4 p. 100 for the anterior cruciate and of 10,5 p. 1u0 for the posterior cruciate ligament in the various goniometric positions. Traction with the Instron apparatus using whole knee with preserved bony attachments revealed an elastic resistance (yield point) of the ligament of about 50 kg, 60 kg and 30 kg (for human, dog and cat respectively) with elastic elongation (at the yield stress) of 25 p. 100, 35 p. 100 and 45 p. 100 (respectively). Trials on the polyethylene prosthetic ligament used at the present time for replacement of cruciate ligaments in humans showed an elastic resistance of only 16 kg with an elasticity of only 1,4 p. 100. The major differences between the physical properties of the artificial and natural ligaments that we have studied in experimental conditions incite our serious doubt as to the value for the practical use of such a prosthesis and provoque strongly the necessity of search for alternative synthetic or other material more suitable for the task in question.

Proposed involvement of an internal promoter in regulation and synthesis of mitochondrial and cytoplasmic leucyl-tRNA synthetases of Neurospora.

Genetic analysis of an electrophoretic variant of the mitochondrial leucyl-tRNA synthetase [L-leucine:tRNALeu ligase (AMP-forming), EC 6.1.1.4] indicates that it is either an allele of or linked closely to leu-5ts, a mutant that is known to produce a cytoplasmic leucyl-tRNA synthetase with an altered affinity for leucine as well as being deficient in the production of the mitochondrial enzyme. Immunological analysis indicates that the two synthetases have little, if any, structural homology. The pattern of synthesis of the enzymes in leu-5ts revertants, the reciprocal relationship of the production of the two enzymes in response to a negative regulatory element, presumably of mitochondrial origin, as well as the lack of detectable structural homology, led to the proposal that the phenotype of leu-5ts results from a mutational alteration in the structural gene for the cytoplasmic enzyme in a region involved in the initiation of transcription of the adjacent gene for the mitochondrial enzyme.

Prosthetic replacement of the anterior cruciate ligament in dogs.

Prosthetic cruciate ligaments are now used clinically. Long-term results are not yet available and for that reason an attempt has been made to reproduce the clnical situation in dogs. Post-traumatic osteoarthritis was inevitably noted following simple excision of the anterior cruciate ligament in a control group of 10 animals. Different prosthetic materials were used and their breaking point was compared with that of normal anterior cruciate ligaments. The longest follow-up period was 6 months. Although some animals had no clinically demonstrable instability, at autopsy all prosthetic ligaments were noted to have failed. The degree of post-traumatic osteoarthritis was directly related to the duration of follow-up. The causes of failure of the prosthetic ligament do not appear to be related to the method of anchorage to bone but rather to the type of prosthetic material used. Although the tensile strength may occasionally have been sufficient, the materials did not have the required elastic characteristics to meet the physiologic demands of a normal cruciate ligament.